Bug 2530594 - CVE-2026-56855 docker-buildx: golang.org/x/crypto/ssh: Denial of Service via crafted messages [fedora-all]
Summary: CVE-2026-56855 docker-buildx: golang.org/x/crypto/ssh: Denial of Service via ...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: docker-buildx
Version: rawhide
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Maxwell G
QA Contact:
URL:
Whiteboard: {"flaws": ["6149aca5-d0d4-472f-b5bb-7...
Depends On:
Blocks: CVE-2026-56855
TreeView+ depends on / blocked
 
Reported: 2026-09-09 09:13 UTC by jkelly
Modified: 2026-09-11 17:22 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:

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Description jkelly 2026-09-09 09:13:10 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a protocol error and tear the connection down instead of buffering and blocking.
Comment 1 Brad Smith 2026-09-11 17:22:26 UTC 
Confirmed

    {
      "vulnerability": {
        "@id": "https://pkg.go.dev/vuln/GO-2026-6355",
        "name": "GO-2026-6355",
        "description": "Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh",
        "aliases": [
          "CVE-2026-56855"
        ]
      },
      "products": [
        {
          "@id": "Unknown Product",
          "subcomponents": [
            {
              "@id": "pkg:golang/golang.org%2Fx%2Fcrypto.0"
            }
          ]
        }
      ],
      "status": "affected"
    }
  ]
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